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Viscosity-molecular weight relationship for cellulose solutions in either NMMO monohydrate or cuen

Authors

  • John Eckelt,

    1. Institut für Physikalische Chemie der Johannes Gutenberg-Universität Mainz and Materialwissenschaftliches Forschungszentrum der Universität Mainz, Welder-Weg 13, D-55099 Mainz, Germany
    2. WEE-Solve GmbH, Auf der Burg 6, D-55130 Mainz, Germany
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  • Anja Knopf,

    1. Institut für Physikalische Chemie der Johannes Gutenberg-Universität Mainz and Materialwissenschaftliches Forschungszentrum der Universität Mainz, Welder-Weg 13, D-55099 Mainz, Germany
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  • Thomas Röder,

    1. Lenzing AG, Department FE, A-4860-Lenzing, Austria
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  • Hedda K. Weber,

    1. Kompetenzzentrum Holz GmbH (Wood K plus), A-4021 Linz, Austria
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  • Herbert Sixta,

    1. Helsinki University of Technology, 02150 Espoo, Finland
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  • Bernhard A. Wolf

    Corresponding author
    1. Institut für Physikalische Chemie der Johannes Gutenberg-Universität Mainz and Materialwissenschaftliches Forschungszentrum der Universität Mainz, Welder-Weg 13, D-55099 Mainz, Germany
    • Institut für Physikalische Chemie der Johannes Gutenberg-Universität Mainz and Materialwissenschaftliches Forschungszentrum der Universität Mainz, Welder-Weg 13, D-55099 Mainz, Germany
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Abstract

The intrinsic viscosities, [η], of nine cellulose samples, with molar masses from 50 × 103 to 1 390 × 103 were determined in the solvents NMMO*H2O (N-methyl morpholin N-oxide hydrate) at 80°C and in cuen (copper II-ethlenediamine) at 25°C. The evaluation of these results with respect to the Kuhn–Mark–Houwink relations shows that the data for NMMO*H2O fall on the usual straight line in the double logarithmic plots only for M ≤ 158 103; the corresponding [η]/M relation reads log ([η]/mL g−1) = –1.465 + 0.735 log M. Beyond that molar mass [η] remains almost constant up to M ≈ 106 and increases again thereafter. In contrast to NMMO*H2O the cellulose solutions in cuen behave normal and the Kuhn–Mark–Houwink relation reads log ([η]/mL g−1) = −1.185 + 0.735 log M. Possible reasons for the dissimilarities of the behavior of cellulose in these two solvents are being discussed. The comparison of three different methods for the determination of [η] from viscosity measurements at different polymer concentrations, c, demonstrates the advantages of plotting the natural logarithm of the relative viscosities as a function of c. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

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